As conventional techniques to attain a spatial resolution scalability of pictures, there have been those implementing, in a hierarchical encoding system with two layers being a base layer and an enhancement layer, for instance, processing signals of pictures input with the same spatial resolution as the enhancement layer, for a decimation into a spatial resolution of the base layer, followed by an encoding at the base layer, making a prediction using a correlation between those signals decoded along with the base layer encoding and spatially interpolated as signals having the same spatial resolution as the enhancement layer and those signals of pictures input with the same spatial resolution as the enhancement layer, encoding signals of errors in the prediction, and having a combination of encoded bit streams obtained there and bit streams obtained by the base layer encoding, multiplexed and transmitted to a decoding system, the multiplexed combination of encoded bit streams being decoded in reverse at the decoding system. (Refer to Patent Literature 1.)